Floating Core for Glass Insert Molding Method and Apparatuses Therefrom

ABSTRACT

A tool ( 1000 ) includes a mold defining a cavity ( 1002 ). The cavity can be for receiving a glass layer ( 402 ). A floating core insert ( 1001 ) can be placed in the cavity to apply a preloading force against a first major face of the glass layer, preclude an overmolding operation on the first major face, and allow overmolding only on minor faces of the glass layer when polymeric material ( 1100 ) is injected into runners ( 1018,1019,1020 ) of the tool.

RELATED APPLICATION

This application claims priority to U.S. Utility patent application Ser.No. 13/964,241 filed Aug. 12, 2013 and claims priority under 35 U.S.C.§119(e) to U.S. Patent Application Ser. No. 61/819,707, the disclosuresof which are incorporated by reference herein in their entirety.

BACKGROUND

Technical Field

This disclosure relates generally to molding, and more particularly toinsert molding.

Background Art

Injection molding of plastic parts is important for many electronicproducts. Injection molding processes known as “insert molding” havebeen used in conjunction with metal parts. Insert molding is alsocommonly referred to as “over-molding.” Illustrating by example,electrical connectors that include metal components disposed in aplastic housing may be formed by insert molding.

While the insert molding process allows for the formation of complexshapes and dimensional control, plastic parts themselves have qualitiesthat are often undesirable. For example, many insert-molded parts arequite thick and have problematic plastic termination lines. Such partsare less suitable for use in modern electronic equipment due to the factthat consumers are demanding smaller and thinner devices. It would beadvantageous to have an improved process that yielded better parts.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separate viewsand which together with the detailed description below are incorporatedin and form part of the specification, serve to further illustratevarious embodiments and to explain various principles and advantages allin accordance with the present disclosure.

FIG. 1 illustrates a prior art insert molded article.

FIG. 2 illustrates a sectional view of the prior art insert moldedarticle.

FIG. 3 illustrates view of a portion of the prior art insert moldedarticle.

FIG. 4 illustrates an explanatory embodiment of one insert molded partconfigured in accordance with one or more embodiments of the disclosure.

FIG. 5 illustrates a sectional view of one explanatory embodiment of oneinsert molded part configured in accordance with one or more embodimentsof the disclosure.

FIG. 6 illustrates a top plan view of a portion of one explanatoryembodiment of one insert molded part configured in accordance with oneor more embodiments of the disclosure.

FIG. 7 illustrates a bottom plan view of a portion of one explanatoryembodiment of one insert molded part configured in accordance with oneor more embodiments of the disclosure.

FIG. 8 illustrates a sectional view of one explanatory embodiment of oneinsert molded part configured in accordance with one or more embodimentsof the disclosure.

FIG. 9 illustrates a sectional view of one explanatory embodiment of oneinsert molded part configured in accordance with one or more embodimentsof the disclosure.

FIG. 10 illustrates a sectional view of one explanatory embodiment ofone insert molded part configured in accordance with one or moreembodiments of the disclosure.

FIG. 11 illustrates a sectional view of one explanatory embodiment ofone insert molded part configured in accordance with one or moreembodiments of the disclosure.

FIG. 12 illustrates a tool configured in accordance with one or moreembodiments of the disclosure executing a step of a method in accordancewith one or more embodiments of the disclosure.

FIG. 13 illustrates a tool configured in accordance with one or moreembodiments of the disclosure executing a step of a method in accordancewith one or more embodiments of the disclosure.

FIG. 14 illustrates a tool configured in accordance with one or moreembodiments of the disclosure executing a step of a method in accordancewith one or more embodiments of the disclosure.

FIG. 15 illustrates an explanatory method in accordance with one or moreembodiments of the disclosure.

FIG. 16 illustrates various embodiments of the disclosure.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are now described in detail. Referring tothe drawings, like numbers indicate like parts throughout the views. Asused in the description herein and throughout the claims, the followingterms take the meanings explicitly associated herein, unless the contextclearly dictates otherwise: the meaning of “a,” “an,” and “the” includesplural reference, the meaning of “in” includes “in” and “on.” Relationalterms such as first and second, top and bottom, and the like may be usedsolely to distinguish one entity or action from another entity or actionwithout necessarily requiring or implying any actual such relationshipor order between such entities or actions. Also, reference designatorsshown herein in parenthesis indicate components shown in a figure otherthan the one in discussion. For example, talking about a device (10)while discussing figure A would refer to an element, 10, shown in figureother than figure A.

Embodiments of the disclosure provide a pressure-reinforced floatingcore insert that can be placed in a cavity of a mold used in an insertmolding process. Advantageously, use of the floating core insert allowsa glass insert-molded article, such as a fascia assembly for a portableelectronic device, to have no step or other feature on either the topsurface or the bottom surface of the glass. Moreover, using the floatingcore insert advantageously results in no flash along the mold partingline. In one or more embodiments, a runner is created in the floatingcore insert so that plastic or other polymeric material can pass throughthe runner when being introduced into the core. The polymeric materialin the runner provides a loading force to a glass layer disposed in thecavity. Accordingly, this results in pressure pushing downward on theglass layer. The pressure closes any gaps or space between the floatingcore insert and the glass layer, resulting in a finished product that isboth flash-free and step-free along its major faces.

FIG. 1 illustrates a prior art glass article 100 that has beenmanufactured using a prior art insert molding process. Such a process isdescribed in US Published Patent Application No. 2010/0285260 toBookbinder et al., which is incorporated by reference herein for allpurposes.

The prior art glass article 100 a glass article 100 includes a glasssubstrate 102 and a polymer overmold 104. The glass substrate 102 has afirst face 106, a second face (108) located opposite the first face 106,and a perimeter edge. The polymer overmold 104 is attached to the entireperimeter edge of the glass substrate 102.

FIGS. 2 and 3 illustrate a sectional view and plan portion view,respectively, of the prior art glass article 100 as indicated by thesection lines shown in FIG. 1. As shown in FIG. 2, the polymer overmold104 attaches to the first face 106, the second face 108, and the minorface 107 joining the first face 106 and the second face 108.

This “c-shaped” wraparound can cause various problems in practice. Afirst problem is that there is a sufficient amount of heat delivered tothe glass substrate 102 that it can warp during molding, therebyrendering it unusable for an electronic device. A second problem is thatgaps 109 can form between the glass substrate 102 and the polymerovermold 104. Experimental testing has shown that gaps as large as 0.08millimeters can arise using the process of the '260 application. Atbest, when the gap 109 appears, the glass substrate will become loosewithin the polymer overmold 104. A worse scenario occurs when the priorart glass article 100 is used in an electronic device, as water, dust,and debris can sometimes pass through the gap 109 into the device,thereby compromising reliability.

A third problem is shown in FIG. 3. As glass passes over the major facesof the glass substrate 102, which is the second face 108 in FIG. 3, awavy and unsightly cosmetic edge results. Experimental testing has shownthat this wavy edge can have variation 309 of about 0.015 millimeters,which is not only unsightly, but causes the glass substrate 102 to againbecome loose.

Embodiments of the present disclosure eliminate all of these problems byproviding a method and system for insert molding that does not allowpolymer to attach to the major faces of a glass substrate. In oneembodiment, a floating core insert is preloaded against a glass layerprior to introducing polymeric material into the tool. This preloadingseats the glass layer within the cavity and allows the polymericmaterial to pass only about the minor faces of the glass layer. As aresult, advantageously, wavy cosmetic lines and gaps are eliminated.Moreover, the resulting part allows for thinner and sleeker electronicdevice designs.

Turning now to FIG. 4, illustrated therein is an explanatory embodimentof an apparatus 400 configured in accordance with one or moreembodiments of the disclosure. For illustrative purposes, the apparatus400 will be described as a fascia assembly for a portable electronicdevice. However, it will be obvious to those of ordinary skill in theart having the benefit of this disclosure that the apparatus 400 can beany of a number of other devices that employ a glass layer 402 with apolymer overmold 404 applied by an insert molding process. Note thatwhile glass is used as an explanatory material for discussion purposes,layers of other material could be substituted for the glass layer 402.For example, a polycarbonate layer could be substituted for the glasslayer 402. Accordingly, the glass layer 402 is representative for anynumber of substrate layers made from other materials that will beobvious to those of ordinary skill in the art having the benefit of thisdisclosure.

As used herein, a “fascia assembly” is a covering or housing for anelectronic device, which may or may not be detachable when theelectronic device is finally assembled. Suitable materials formanufacturing the fascia assembly include clear or translucent plasticfilm, glass, ceramics, plastic, or reinforced glass. The glass layer 402of FIG. 4 will be used for illustrative purposes. Where reinforced glassis used, such glass can comprise glass strengthened by a process such asa chemical or heat treatment.

The glass layer 402 may also include a ultra-violet barrier, which canbe applied before or after the insert molding process. Such a barrier isuseful both in improving the visibility of display assembly above whichthe apparatus 400 is disposed. The barrier can also be used to protectprotecting internal components of the electronic device.

Selective printing can be deposited on the glass layer 402 as well. Whenthe apparatus 400 is used as a fascia assembly, it can be used withelectronic devices having a display, a keyboard, or both. Where printingis used, in one embodiment the printing is disposed on the rear face(408) of the glass layer 402. By printing on the rear face (408) of theglass layer 402, the front face 406 remains smooth and glossy.Additionally, the printing, being disposed on the inside of the device,is protected from wear and abrasion. It will be clear to those ofordinary skill in the art having the benefit of this disclosure that theprinting could equally be done on the front face 406. There may even beadvantages in doing so, including offering unique textural effects onthe exterior of the electronic device. Examples of how fascia assembliescan be used in electronic devices are found in commonly assigned,copending U.S. Ser. No. 11/427,444 to Baw et al., filed Jun. 29, 2006,which is incorporated herein by reference for all purposes.

The front face 406 and the rear face (408) each comprise the major facesof the glass layer 402. The side edges constitute the minor faces of theglass layer 402. This will be more readily visible with reference toFIG. 5 below.

In one or more embodiments, the glass layer 402 can be substantiallyplanar. In other embodiments, the glass layer 402 can be contoured, suchas having a convex front face 406, concave rear face (408), or both.Optional features can be incorporated into the glass layer 402,including microlens arrays, filters, lenses, and so forth. Otherconfigurations of the glass layer 402 will be obvious to those ofordinary skill in the art having the benefit of this disclosure.

While the illustrative embodiment of FIG. 4 depicts a glass layer 402that is substantially rectangular shaped glass layer 402, those ofordinary skill in the art having the benefit of this disclosure willrecognize that the glass layer 402 may be formed in other shapes aswell. For example, and without limitation, the shaped glass substratemay be circular, square or any other regular or free form shape.

Turning to FIG. 5, illustrated therein is a sectional view of theapparatus (400). FIGS. 6-7 illustrate a sectional view and plan portionview, respectively, of the apparatus (400). Reference of the sectionaland plan portion views for each of FIGS. 5-7 are identified in FIG. 4 byfigure number. These figures, and in particular FIG. 5, illustrate oneof the primary advantages offered by embodiments of the disclosure,namely, that all portions of the polymer overmold 404 attaching to theglass layer 402 attach along the minor faces 409,410,411. Thiscompletely eliminates the problems of gaps and unsightly wavy cosmeticlines along the major faces of the glass layer 402, which are the frontface 406 and the rear face 408. No polymer attaches to either majorface, i.e., either to the front face 406 or the rear face 408, in thisembodiment.

In this illustrative embodiment, the rear face 408 has less area thanthe front face 406 due to the fact that the minor faces 409,410,411 arestair-stepped inward from an outer perimeter of the rear face 408 to theouter perimeter of the front face 406. In this illustrative embodiment,there is a single stair step. However it will be obvious to those ofordinary skill in the art that the minor faces 409,410,411 could definemore stair steps.

In this illustrative embodiment, the polymer overmold 404 extends from aplane defined by the rear face 408 to a termination angle 512 disposedbeyond a perimeter of the rear face 408. Accordingly, the “compositerear face” is defined by the rear face 408 and portions of the polymerovermold between minor face 411, disposed at the perimeter of the rearface, and termination angle 512.

Stair steps are not the only minor face geometry that can be used tomake the front face 406 have a lesser area than the rear face 408.Turning now to FIGS. 8-11, illustrated therein are alternate apparatuseshaving different minor face geometries. Each geometry results, however,in a first major face having less area than a second major face. Whilethe convention to this point has been to have a front side smaller thanthe rear side, it should be noted that the opposite convention can alsobe used. The front face can be larger than the rear face in one or moreembodiments. The illustrative embodiments of FIGS. 8-11 do not includethe termination angle (512) shown in FIG. 5. However, it will be clearto those of ordinary skill in the art having the benefit of thisdisclosure that they could so as to define a composite face having aplanar surface area greater than the minor faces of each figure.

Beginning with FIG. 8, illustrated therein is an apparatus where theglass layer 802 has a first major face 806, a second major face 808, andone or more minor faces 809. In this illustrative embodiment, the minorface 809 has a curvilinear shape. The illustrative curvilinear shapeincludes one convex portion and one concave portion. That thecurvilinear shape begins at a perimeter of the second major face 808,moves through a first convex portion to a first concave portion to theperimeter of the first major face 806 results in the first major face806 having less area than the second major face 808. As with theembodiment of FIG. 4, the polymer overmold 804 attaches only to theminor face 809, and does not attach to either the first major face 806or the second major face 808.

In any of the embodiments herein, the minor faces 809 can be continuousabout a perimeter of the glass layer 802, or may be discontinuous. Wherecontinuous, the minor face 809 can have the same shape along theentirety of the perimeter. Where discontinuous, the minor face 809 cantake different shapes along the perimeter. Illustrating by example, somesegments could be stair stepped, as shown in FIG. 5, while othersegments could be curvilinear, as shown in FIG. 8, or take other shapes.Other configurations for the minor faces will be obvious to those ofordinary skill in the art having the benefit of this disclosure.

Turning now to FIG. 9, illustrated therein is an apparatus where theglass layer 902 has a first major face 906, a second major face 908, andone or more minor faces 909. In this illustrative embodiment, the minorface 909 has a linear shape. The illustrative linear shape tapers inwardfrom a perimeter of the second major face 908 to a perimeter of thefirst major face 906, resulting in the first major face 906 having lessarea than the second major face 908. As with the embodiments above, thepolymer overmold 904 attaches only to the minor face 909, and does notattach to either the first major face 906 or the second major face 908.

Turning to FIG. 10, illustrated therein is an apparatus where the glasslayer 1002 has a first major face 1006, a second major face 1008, andone or more minor faces 1009,1010,1011. In this embodiment, the rearface 1008 again has less area than the front face 1006 due to the factthat the minor faces 1009,1010,1011 are stair-stepped inward from anouter perimeter of the rear face 1008 to the outer perimeter of thefront face 1006. In this illustrative embodiment, there is a singlestair step. However it will be obvious to those of ordinary skill in theart that the minor faces 1009,1010,1011 could define more stair steps.

Turning now to FIG. 11, illustrated therein is an apparatus where theglass layer 1102 has a first major face 1106, a second major face 1108,and one or more minor faces 1109. In this illustrative embodiment, theminor face 1109 has a linear shape. The illustrative linear shape isvertical from a perimeter of the second major face 1108 to a perimeterof the first major face 1106, resulting in the first major face 1106having the same area as the second major face 1108. The polymer overmold1104 attaches only to the minor face 1109, and does not attach to eitherthe first major face 1106 or the second major face 1108.

The embodiments of FIGS. 4-11 can be manufactured using a toolconfigured in accordance with one or more embodiments of the disclosure.Turning now to FIG. 12, illustrated therein is one explanatoryembodiment of such a tool 1200. The novel and non-obvious tool 1200 ofFIG. 12 advantageously includes a floating core insert 1201 that isallowed to “float,” e.g., translate longitudinally (vertically as viewedin FIG. 12) within the cavity 1202 of the tool 1200. In one or moreembodiments, the tool 1200 comprises a three plate cold runner mold.This means that two backing plates 1203,1204 are separable from the moldplates 1205,1206, which are bolted together in this illustrativeembodiment. Advantageously, allowing the floating core insert 1201 and,optionally, the two backing plates 1203,1204 to float allows pressureapplied in the runner system via introduction of polymeric material tobe used to press the glass layer 402 against the core block 1207. Bypressing the front face 406 of the glass layer 402 against a seatingplane 1208 of the core block 1207, and by covering the rear 408 with thebottom surface 1209 of the floating core insert 1201, the glass layer402 can be held in place while polymeric material couples to only theminor faces 409,410,411 of the glass layer 402. This is in contrast toprior art designs where polymeric material had to attach to the majorfaces for proper adhesion in the tool. Accordingly, the compressiveforce applied by the floating core insert 1201 allows for thinner,sleeker designs with improved cosmetics.

The floating core insert 1201 of this illustrative embodiment includesseveral components.

In this embodiment, the floating core insert 1201 includes an upperblock 1210, a lower block 1211, and a flange 1212. The lower block 1211of this illustrative embodiment includes two compressible pads 1213,1214that limit lateral movement of the glass layer 402 when in the coreblock 1207. The compressible pads 1213,1214 are optional. Additionally,one, three, four, or more compressible pads can be used in variousembodiments.

Above the lower block 1211 is the flange 1212. The flange 1212 extendslaterally beyond the lower block 1211 or the upper block 1210 in thisembodiment. The flange 1212 sits within a recess 1215 of mold plate1206. As noted above, the floating core insert 1201 is allowed to float,or translate longitudinally, within the cavity 1202. Inclusion of theflange 1212, which is optional, provides a mechanical device that limitsthe amount of longitudinal translation that occurs. For example, if thefloating core insert 1201 moves too far up or down (as viewed in FIG.12), the flange will hit the floor or ceiling walls of the recess 1215.Accordingly, the floor and ceiling walls of the recess 1215 serve as amechanical stop to prevent the flange 1212, and correspondingly thefloating core insert 1201 from moving beyond a predetermined thresholdwithin the tool 1200. In one embodiment, the predetermined threshold isabout 0.15 millimeters. In another embodiment, the predeterminedthreshold is 0.10 millimeters.

In one embodiment, the upper block 1210 is spring biased against eitherthe flange 1212 or the lower block 1211. In this illustrativeembodiment, two springs 1216,1217 are disposed between the upper block1210 and the flange 1212. These two springs 1216,1217 can cause apreloading force to be applied to the glass layer 402 when the tool 1200is closed in one embodiment. In other embodiments, the two springs1216,1217 provide a pre-seating function. When pressure from theinjected polymer material reaches the upper block 1210, the there can besolid contact between the upper block 1210 and the lower block 1211.Where this occurs, pressure against the glass layer 402 is appliedprimarily from injected polymer material applying pressure to the runnerplate 1250.

In one embodiment, a runner 1218 is cut into the upper block 1210 of thefloating core insert 1201. When polymeric material is introduced intothe tool 1200, it flows through the runner 1218 of the floating coreinsert 1201 into the other runners 1219,1220 of the tool. The pressurewith which the polymeric material is introduced into the tool can beadjusted to apply an additional loading force on the glass layer 402 byincreasing the area flooded with plastic, that is, by adding extra tabs,pads, or lakes. Said differently, when polymeric material passes throughthe runner 1218 of the floating core insert 1201, the pressure causesthe floating core insert to press downward against the glass layer 402.This pressure reinforces the location achieved by the preloading forceof the springs 1216, 1217, retaining the glass layer 402 in a constantlocation within the core block 1207. The pressure creates the conditionswhereby the seamline at (406) and (408) are clean and flash-free.

In one embodiment, the various components of the floating core insert1201 are configured to apply a preloading force against a first majorface of the glass layer 402, preclude an overmolding operation on thefirst major face, and allow overmolding only on minor faces of the glasslayer 402 when polymeric material is injected into remaining portions ofthe cavity not filled by the glass layer and the floating core insert,i.e., runners 1218,1219,1220. In one embodiment, by allowing thefloating core insert 1201 and the two backing plates 1203,1204 to float,pressure in the runner system, i.e., in runners 1218,1219,1220, can beused to press the glass plate against the seating plane 1208 of the coreblock 1207. Embodiments of the disclosure can be used any shape of glasslayer 402, including the various glass layer embodiments describedabove.

FIGS. 12-14, collectively, also illustrate a method for manufacturing anapparatus configured in accordance with embodiments of the disclosure aswell. At FIG. 12, a first step is being performed. Specifically, theglass layer 402 is being positioned in the cavity 1202 of the tool 1200.At this step, the floating core insert applies a preloading forceagainst a first major face (the rear face 408 in this example) of theglass layer 402 to hold the glass layer 402 in place in core block 1207.

At FIG. 13, the tool 1200 is closed. Polymeric material 1300 is thenintroduced into the runners 1218,1219,1220 by injection. Thisintroduction applies an additional loading force against the first majorface by way of the pressure applied from the polymeric material 1300passing through the runner 1218 in the floating core insert 1201. Itfurther causes the polymeric material 1300 to fill the voids 1301,1302of the core so as to become the polymer overmold (404) of the resultingapparatus. In one embodiment, the introduction of the polymeric material1300 is done in a controlled manner so as to regulate the application ofthe additional loading force. For example, in one embodiment, theinjecting comprises altering an introduction force of the polymericmaterial 1300 into the mold or tool 1200 across time. This can include,in one embodiment, introducing the polymeric material 1300 into thecavity 1202 with a lesser force at an earlier time and a greater forceat a later time. At FIG. 14, the tool 1200 is opened, thereby revealingthe finished apparatus 400.

Turning now to FIG. 15, illustrated therein is a flow chart of anothermethod 1500 of manufacturing in accordance with one or more embodimentsof the disclosure. At step 1501 a glass layer is positioned in thecavity of a tool or mold. At step 1502, a floating core insert is placedin the cavity to apply a preloading force against a first major face ofthe glass layer. In one embodiment, the preloading force of step 1502 isapplied by one or more springs of the floating core insert disposedbetween a first portion of the floating core insert and a second portionof the floating core insert. In one or more embodiments, this step 1502includes allowing the floating core insert to float within the cavityduring the molding process.

At optional step 1503, lateral movement of the glass layer within thecavity is reduced. In one embodiment, step 1503 is performed bydisposing one or more compressible pads along the floating core insert.The one or more compressible pads can then be biased between thefloating core insert and the glass layer.

At optional step 1504, longitudinal movement or translation of thefloating core insert can be limited. In one embodiment, this step 1504includes limiting translation with a flange of the floating core insertand a recess of the mold complementary to the flange as described above.In one embodiment, the floating occurring at step 1502 is limited atstep 1504 so as to be less than 0.10 millimeters.

At step 1505, polymeric material is introduced into the cavity byinjection. In one embodiment, this step 1505 applies an additionalloading force against the first major face of the glass layer by passingthe polymeric material through a runner defined in the floating coreinsert. As noted above, this step 1505 can be performed in a controlledmanner. For example, in one embodiment this step includes altering anintroduction force of the polymeric material into the mold across time.In one embodiment, this step 1505 includes introducing the polymericmaterial into the cavity with a lesser force at an earlier time and agreater force at a later time. At this step 1505 the polymeric materialforms an overmold on the glass layer by attaching to only the minorfaces. At step 1506, the mold or tool is opened and the apparatus isremoved.

FIG. 16 illustrates various embodiments of the disclosure. At 1601, atool comprises a mold defining a cavity. At 1601 the cavity is for atleast receiving a glass layer. At 1601, a floating core insert is placedin the cavity to apply a preloading force against a first major face ofthe glass layer, preclude an overmolding operation on the first majorface, and allow overmolding only on minor faces of the glass layer whenpolymeric material is injected into remaining portions of the cavity notfilled by the glass layer and the floating core insert.

At 1602, the floating core insert of 1601 comprises one or more springsto apply the preloading force. At 1603, the floating core insert of 1601defines a runner for the polymeric material to apply an additionalloading force against the first major face. At 1604 the floating coreinsert of 1601 comprises a flange. At 1604 the cavity defines a recesscomplementary to the flange to limit longitudinal movement of thefloating core insert.

At 1605 the tool or mold comprises a three plate cold runner mold. Notethat the floating core insert may also be used with other molds,including hot runner molds, two plate cold runner molds, and so forth.At 1606 the floating core insert of 1601 comprises one or morecompressible pads biased between the floating core insert and the glasslayer.

At 1607, an apparatus comprises a glass substrate defining a first majorface, a second major face, and one or more minor faces. At 1607, thesecond major face has less area than the first major face. At 1607 apolymer overmold attached only to the one or more minor faces.

At 1608 the minor faces of 1607 define a concave feature between thesecond major face and the one or more minor faces. At 1609 the apparatusof 1607 comprises a fascia assembly for a portable electronic device.

In the foregoing specification, specific embodiments of the presentdisclosure have been described. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the present disclosure as set forthin the claims below. Thus, while preferred embodiments of the disclosurehave been illustrated and described, it is clear that the disclosure isnot so limited. Numerous modifications, changes, variations,substitutions, and equivalents will occur to those skilled in the artwithout departing from the spirit and scope of the present disclosure asdefined by the following claims. Accordingly, the specification andfigures are to be regarded in an illustrative rather than a restrictivesense, and all such modifications are intended to be included within thescope of present disclosure. The benefits, advantages, solutions toproblems, and any element(s) that may cause any benefit, advantage, orsolution to occur or become more pronounced are not to be construed as acritical, required, or essential features or elements of any or all theclaims.

What is claimed is:
 1. A tool, comprising: a mold defining a cavity, thecavity for receiving a substrate; and a floating core insert to: apply apreloading force against a first major face of the substrate; precludean overmolding operation on the first major face; and allow overmoldingonly on minor faces of the substrate when polymeric material is injectedinto runners of the mold.
 2. The tool of claim 1, wherein the tool isconfigured to apply an additional loading force against the first majorface when passing the polymeric material into the runners of the mold.3. The tool of claim 2, wherein the floating core insert defines therunners of the mold for the polymeric material to apply the additionalloading force against the first major face.
 4. The tool of claim 2,wherein the additional loading force presses the first major face of thesubstrate against a seating plane of the cavity.
 5. The tool of claim 1,the floating core insert comprising one or more springs to apply thepreloading force.
 6. The tool of claim 1, the floating core insertcomprising a flange, the cavity defining a recess complementary to theflange to limit longitudinal movement of the flange.
 7. The tool ofclaim 1, the mold comprising a three plate cold runner mold.
 8. The toolof claim 1, the floating core insert comprising one or more compressiblepads biased between the floating core insert and the substrate.
 9. Thetool of claim 1, wherein the substrate is a glass layer.
 10. The tool ofclaim 1, wherein the additional loading force is effective to create aclean and flash-free seamline between the polymeric material and thefirst major face.
 11. The tool of claim 1, further comprising limitinglongitudinal translation of the floating core insert with a flange ofthe floating core insert and a recess of the mold complementary to theflange.
 12. An apparatus, comprising: a substrate defining a first majorface, a second major face, and one or more minor faces, the second majorface having less area than the first major face; a polymer overmoldattached only to the one or more minor faces.
 13. The apparatus of claim12, the substrate defining a concave feature between the second majorface and the one or more minor faces.
 14. The apparatus of claim 12, thesubstrate defining a curvilinear shape between the second major face andthe first major face.
 15. The apparatus of claim 14, wherein thecurvilinear shape includes one convex portion and one concave portion.16. The apparatus of claim 12, the substrate defining a linear shapetapering inward from a perimeter of the first major face to a perimeterof the second major face.
 17. The apparatus of claim 12, wherein the oneor more minor faces includes three minor faces, the three minor facesstair-stepped inward from an outer perimeter of the first major face toan outer perimeter of the second major face.
 18. The apparatus of claim12, the substrate comprising a glass substrate.
 19. The apparatus ofclaim 12, wherein the substrate, on the second major face, is convex.20. The apparatus of claim 12, the substrate, on the second major face,is circular.